For statement and similar mail, such as might be used by telephone companies, utility companies and others who send several statement pages to each customer, a smaller businesses size envelope such as a number 10 may not be large enough. A larger size envelope referred to as a flat or half flat size envelope then typically may be used for these mailings. However, large envelopes of sizes such as a 9″×12″ or a 6″×9″ are typically not used for sending transactional mail to a lock box or remittance center, such as when a customer sends a payment or a direct mail solicitation reply by mail. Instead, and typically included in a statement mailing such as described, a separate reply envelope for the customer to return their payment to complete the transaction is included.
The main reason a reply envelope is added is because the larger envelopes are not the appropriate size for most high-speed automated remittance equipment. They are taller than the desired height of approximately 3.5″ to 4.4″. The reply envelope is only needed for remittance and adds costs because it is a separate envelope that needs to be manufactured, printed, shipped, stored, and inserted. Generally when a customer sends a payment for a bill or invoice by mail they send a payment coupon with their check in the reply envelope. A larger envelope that can carry multiple pages on the outgoing mailing is not required for the return when a single check and coupon are returned. For this purpose a smaller envelope is sufficient. In addition, a smaller reply envelope fits the optimal size requirements for remittance equipment, allowing the most efficiencies and cost savings for returned mail.
A majority of mail that is returned for paying a bill or responding to a solicitation is what is referred to as a reply envelope. The typical reply envelope is a No. 9 envelope which is approximately 3.875 inches high. Because there is a general conformity for the standard reply envelope size, companies responsible for collecting and processing the return mail optimize their machines to this standard size for speed and accuracy. Sizes outside the standard size are either unable to be processed through automated equipment or can slow the automated process down, costing companies extra money in processing and delaying payment from the customer. Thus a larger envelope for the outgoing is not feasible for remittance and a smaller reply size helps to ensure automated remittance processing and on time banking and payment.